If you have Vista, disable UAC before installing WSM. See this thread for more info.

All the games require the latest game patch; the exception is Torment, which allows you to play either the patched 4CD version and the (already patched) 2CD version. Throne of Bhaal requires the 'official' 26498 patch and is not compatible with the 'beta' 26499. It is possible that a game crack will not be compatible with this mod.

If you get the message "EXE patching failed", then it means that either you're using an unsupported/cracked version of the game executable, or you installed accidentally the WSM twice. Try fully uninstalling your game and reinstalling from the CDs, then applying the proper patches (see the point above). If that fails, report your game version.

In particular, WSM must be uninstalled on the 'base' BG2 installation when you install Tutu/Easytutu, or create multiple installs of any game.

If you get the message "ERROR: BIFF [./AR0100.BIF] cannot be loaded" (or something similar), you need to apply a full install of the game.

BG1 and PST do not require a new save game anymore; however, if you change save game resolution, all your visited areas will become fully unexplored. If you plan to play a game at multiple resolutions, Widescreen allows you to save your games at a common resolution, independent of the game resolution.

An additional problem in PST and TotSC is that, due to a complex area enlargment system under the hood, on smaller areas (mostly the "Ambush" ones) the East and South "travel to Worldmap" triggers do not work. If this makes it impossible to leave any area, contact me detailing the resolution you're running and the area that gives you troubles. Isayia has tested all of TotSC at 1280x1024 at least.

Not all the GUIs are ported in the optimal way to the larger resolution. The main GUI (where you choose "Start Game", "Options",...) as well all various screens ("Load", "Mage Spells"...) are centered, with a black cover (SoA, HoW, ToB, IWD2) or forced to the upper left (PST, TotSC). The main game GUI (where you can move your characters, attack people etc.) is stretched properly, enlarging even the dialogue screen (SoA, ToB, HoW) or might display black bars (PST, IWD2, TotSC).

Nicer GUIs for BG1 and PST are available via an external mod (to be install in both cases after Widescreen).

If neither of these applies to your problem, feel free to open a topic to report your problem. Be advised that, in the event that you're asking a question already answered here, your question will be unanswered.